At Mach 5 and beyond, things heat up pretty fast

Sunday, February 19th, 2023

The U.S. might be slipping behind Russia, or even China, in the race to develop hypersonic missiles, but that might be because the U.S. military has its sights set on a bigger prize, a hypersonic bomber:

Meet the Air Force’s secret hypersonic bomber: the Expendable Hypersonic Multi-mission ISR (intelligence, surveillance and reconnaissance) and Strike program, a.k.a. Project Mayhem.

The mighty bomber would have a few advantages over its missile-based adversaries, but the big one would be usability. Where missiles like the Kinzhal, Zircon, and China’s Dongfeng-17 are expensive (around $100 million) one-shots, a hypersonic plane traveling in excess of Mach 5 — Project Mayhem would reportedly travel Mach 10 — could be refueled and used again, and again, and again.

The idea of a hypersonic plane dates back to the Space Race, culminating in the North American X-15A-2 record-breaking Mach 6.7 flight in 1967. Further aerospace advancements created mechanical wonders like the supersonic SR-71. Project Mayhem would likely use a multi-cycle propulsion system, employing a jet engine to reach Mach 3 before transitioning to an air-breathing scramjet for hypersonic speeds. But designing a reusable plane at such speeds comes with serious limitations.

At Mach 5 and beyond, things heat up pretty fast thanks to friction and air resistance, so any plane hoping to go that fast and survive the experience would need to be cloaked in advanced materials that haven’t even been invented yet. None of this even touches on the fact that maneuverability at such speeds will also be a gargantuan engineering undertaking, and that combining a traditional jet engine with a scramjet has never been successfully accomplished.

Because of this unique operating environment and the necessity of precision-sensitive design, Project Mayhem is turning to model-based engineering (MBE) to digitally construct every system on the hypothetical plane.


  1. Bob Sykes says:

    Both China and Russia have deployed hypersonic weapons, and they are in serial production in both countries. Russia has actually used them in Ukraine.

    Whether the US can develop and deploy hypersonic weapons remains to be seen, but it is likely they can in the next several years.

    I am going to speculate that a hypersonic bomber, if practical, is going to top $20 billion to $50 billion per copy. I base that on the original cost of the B-2 and the likely cost of the B-21.

  2. Adar says:

    There it is in the nutshell from Bob Sykes.

    Cost will be so prohibitive that only a few can ever be made.

    I think the USAF had this concept decades ago called Dyna-Soar.

  3. Altitude Zero says:

    Yes, and didn’t the US quit building the B-70 Valkyrie because we came to the conclusion that super-high speed was just not that great an advantage for a bomber, in this age of sophisticated anti-aircraft missiles? The US is obsessed with manned bombers, and has been for the better part of a century – it may be time to move on.

  4. Jim says:

    If it’s showing up in PR articles, it isn’t very secret, is it? Contrast to NSA’s digital panopticon, NRO’s real-time surveillance of every square inch of the surface of the earth, or CIA’s Joe Biden clone army.

    In other words, I wonder how much the Chair Force paid to have that article placed.

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